You shouldn't need to add your own attributes for these things. You can use event handlers for things like mining speed, and adjust the speed based on if the tool has a prefix/which prefix the tool has.

Idea Similar to quality tools mod, which i enjoy much together with levels mod. Think the attributes of this mod is a bit too OP, especially in modpacks that doesnt use very powerful tools. But otherwise, seems fun. Will follow the progress on this